My dealer just "plugged-in" my Enduro Pro module last week - I got my GSW in early April and the module was not sent with the bike. Yes, it works well in moderate off road gravel / dirt. Not sure about mud ... and have not yet tried it in snow - soon to come, however.
Pro allows you to power the rear wheel around in turns and still maintain anti-lock on the front brake; very nice engineering!
30+ years with RTs...then to F/GS; now *Finally*
the BMW: R1200GSW, factory low seat & lower crash bars;
Touratech: Upper Crash Bars, big foot, pannier rack, ZegaPro panniers;
Fuzeblock, Rigid Dually D2 + yellow covers; Wunderlich bar risers w/ Q-adjust